Islands of Stability, ice-age flips: pre-registration (r1)

This deposit fixes, before anything is computed, two tests of proposition 3 of Islands of Stability (islandsofstability.com) on Greenland's NGRIP ice-core record of the last ice age. C1: were the cold periods (Greenland stadials) memoryless, as a noise-driven reading predicts (Ditlevsen, Andersen and Svensson, 2007), judged by the Weibull shape of their lifetimes? C2: did the warmings keep the claimed 1,470-year clock (Rahmstorf, 2003), judged by a Rayleigh test? Warning signs before each warming are reported descriptively. These questions have been studied, so this is a replication with rules fixed in advance, not a first look. Nothing in this deposit has been computed. The tests use no random numbers; run_test.py requires this record's DOI so that the statistics can only be computed after the dated deposit, and refuses to run unless every frozen file matches lock.json. The data files come from the Centre for Ice and Climate, University of Copenhagen; they are not redistributed here, and data/SOURCE.md gives their sources and SHA-256. Contents of bundle.zip (SHA256SUMS lists a hash for every file): PREREGISTRATION.md: the frozen document (r1), also uploaded on its own; PREREGISTRATION-draft.md is the draft (r0), kept for the record. lock.json and freeze.py: the SHA-256 of every frozen file, and the check (python freeze.py --verify). flips.py, xlsx.py, run_test.py: the analysis, a standard-library reader for the ice-core workbooks, and the runner (python run_test.py --doi ). data/SOURCE.md: where the two ice-core files come from, with their checksums. tests/: unit tests on made-up data (python -m pytest -q tests). Related: the pre-registration of the site's first instrument, snapshot 1 of the Map (10.5281/zenodo.22982434). Drafted with Claude (Anthropic), an AI assistant; every decision recorded in the document was made by the author.